Preliminary studies of schizotypal subjects suggest that this disorder is phenomenologically, genetically, and biologically related to chronic schizophrenia as part of a continuum of schizophrenia-related disorders. However, this relationship remains to be definitively established in clinically identified schizotypal patients, relatively accessible population whose study is less likely to be confounded by chronic neuroleptic use or institutionalization than that of schizophrenic patients. The characterization of the psychobiologic relationship between schizophrenic and clinically identified schizotypal personality disorder patients thus represents an important step in the definition of the nosologic, genetic, and pathophysiologic boundaries of the schizophrenia-related continuum. Towards this end, the objectives of the studies proposed in this application are to evaluate three psychobiologic measures demonstrated to be abnormal in schizophrenic patients and preliminary studies of schizotypal individuals: smooth pursuit eye movement (SPEM) accuracy, the continuous performance task (CPT) and the backward masking test in schizotypal patients; in chronic schizophrenic patients; in comparably symptomatic controls, patients with other non-schizophrenia-related personality disorders; and in normal controls. The Holzman Thought Disorder Inventory (TDI), the Chapman psychosis-proneness scales and the Schedule for Interviewing DSM-III personality Disorders (SlDP) will be administered to characterize the schizophrenia-like psychologic disturbances in the schizotypal and other personality disordered patients, while less specific global and depressive symptomatology will be evaluated by the BPRS and Beck Depression Inventory respectively. Repeat testing of all of these variables at six month intervals for the first year following initial evaluation will enable a determination of the stability of these variables. Comparison of the psychobiologic measures between the groups will test the hypothesis that both schizophrenic and schizotypal patients differ from the two control groups on these measures. Multivariant analyses of the psychobiologic and psychologic variables by factors of time and diagnosis will be employed to help a determine to what extent any diagnostic group differences in the biologic variables are related to less specific state-related symptomatology and to what extent they are related to the "core" schizotypal symptoms of social withdrawal, anhedonia, and subtle thought disorder.